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Archive for December, 2009

What is GWT?

In case you haven’t had a chance to explore, Google Web Toolkit (GWT) is a great new tool for building web applications. At its core, GWT allows developers to code in Java and essentially “compile” to Javascript. But it offers much more: GWT also provides a set of common controls (or widgets) to build UIs and even provides a plugin for Eclipse that allows developers to debug both client and server-side code in the same environment that they write their code. Cross browser compatibility is taken care of for you and if you stay within the confines of GWT, for all practical purposes you’ll think you were building a native Java client/server application.

What’s new in GWT 2.0?

Yesterday Google released Google Web Toolkit 2.0. GWT 2.0 provides a number of improvements but the most important one is the ability to define your UI using markup instead of code. You could always create good old fashion html with GWT, but if you wanted to use the native UI widgets, you’d have to do all the creational work in code. With 2.0 you are now able to use a feature called uiBinder to build your own native GWT widgets (the equivalent of UserControls) all in markup. The cool part is, you can mix html with your GWT markup if you want to.

The Good:

GWT helps developers build complex client/server applications with first class tools in a first class language and target any browser without the need for a plugin. The developer doesn’t have to know anything about Javascript, Html, or cross browser quirks and can use accepted design patterns for building complex web applications.

The Bad:

Before my time, assembly programmers must have argued with C programmers that they could never write code in C that would be as efficient as assembly. They must have argued that there would be certain advanced tasks that couldn’t be done easily in C, and that the compiled C would be bloated by comparison and nearly impossible to read if something went wrong and you needed to inspect your code. This is the same argument GWT faces today from the Javascript camp. Ultimately, a javascript app is still being created under the hood and because of it, GWT developers will never have the same level of control and flexibility as if it had built in Javascript from the beginning. All choices have tradeoffs and this is one of GWT’s.

The Ugly:

The product that GWT allows a developer to create will always only be as good as the browser running it and will be held back by the older browsers that it needs to support. In the near term, in order for the GWT feature set to progress, 2 things have to happen: 1) browsers have to natively start supporting new features (can anyone say HTML5?), and 2) certain features in your GWT app won’t support older browsers. While this is a reasonable way to compete with ASP.NET Webforms, jQuery, and Ruby on Rails, this is not a sustainable path to compete with Flash, Silverlight, or Java FX. Hence…

My opinion on GWT’s long term strategy:

Either GWT will ultimately be positioned as a technology suited for catering to lowest common denominator scenarios or…

Google will have to adopt something similar to the plugin approach. GWT developers will still build their app using GWT the way they do today but if they want access to all those extra goodies that Flash, Silverlight and Java FX have (the ones that are not supported in the current version of HTML or Javascript), GWT will need to build those features into Chrome and allow developers to build apps that require some variation of Chrome (Chrome browser, the Chrome OS, or the Chrome Frame plugin). Google may try to bake these feautres into whatever the next version of HTML is at the time but my guess is that they won’t always be willing to wait around for W3C to agree and will start adding them to Chrome as they need them. In the end, GWT apps that need the latest features will essentially be native Chrome apps built on (for all practical purposes) a Java powered plugin framework.

Personally, I say unless you need a plugin independent app, why wait? Silverlight, Flash, and Java FX give you today everything that GWT will provide tomorrow.

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